News and commentary on what we consider to be the top new schizophrenia research developments most relevant for families, care takers and people who have schizophrenia. Hosted by Farzin Irani (PHD candidate), and Jacob Ballon, (MD candidate).

Search for cognitive trait components of schizophrenia reveals a locus for verbal learning and memory on 4q and for visual working memory on 2q

There is an endless search for genes involved in schizophrenia. The search has been difficult so far because there seem to be many genes affecting a number of functions in the brain. In this study, the authors tried to find genetic loci (loci=position for a gene) contributing to certain cognitive functions, by performing certain statistical analyses of genes collected from 168 Finnish schizophrenia families. Their strategy was unique since it identified the benefits of using traits (traits=characteristics that are inherited from parents) instead of clinical diagnoses. They analyzed traits associated with vulnerability to schizophrenia and those that appeared to be heritable in families.

They found evidence for loci for verbal learning and memory on chromosome 4q21 and for visual working memory on 2q36. Both of these chromosomes have been previously implicated in genetic susceptibility for schizophrenia. Some evidence also emerged for a locus for recognition memory on 10p13 (which other researchers have also found), visual attention on 15q22 and executive function on 9p22. They also found evidence for delayed memory on 8q12, semantic clustering and intrusions on 1q42 and visual attention on 3p25. In addition to these regions, some evidence of linkage was observed for 2q, 6q, 7q, 11q, 13q, 14q, 18q and 22q.

The authors state that their results emphasize the value of trait components in the search for susceptibility loci for complex illnesses. This is because in all these loci the information was increased by looking at quantitative traits instead of just a dichotomous trait definition. Although we have a long way to go before we can clearly identify the genes involved in this complex illness, such work provides another strategy for trying to find these genes so that we can understand their role in affecting the brain. Hopefully in the future, finding the genes involved in schizophrenia can help with early identification and intervention strategies.

All data, including the complete list of markers as well as the two-point and multipoint LOD scores in all samples, can also be found at their website: http://www.ktl.fi/mols/wwwpub.htm.

This work was supported in part by Millennium Pharmaceuticals, Inc., Wyeth-Ayerst Research Division and Emil Aaltonen Foundation (T.H).